Phages for food safety microbiology for food safety

1. Norziela Anuar GS61337
Phages For Food Safety
Phages, formally known as bacteriophages, are viruses that solely kill and selectively
target bacteria. Bacteriophages are naturally occurring biological entities that are
separated from the environment and are among the most frequent biological entities
in nature. Because of the specificity of bacteriophages, it provides a unique opportunity
to target pathogenic bacteria in foods without affecting the natural microflora of foods.
The mechanism of bacteriophages is each phage specializes in overtaking certain
strains of bacteria—for example, Staphylococcus spp, Streptococcus spp, and
Escherichia coli—which they target and utilise as a host to multiply. To invade a host
microbe, a phage uses proteins on its own surface to bind with proteins on the host
cell, creating a passageway through which the phage can inject its genes (Picture 1).
This mechanism is called bacteriophage lysis.
Picture 1

2. Bacteriophages are used for food safety applications as a biocontrol, bio sanitation
and biopreservation to eliminate pathogenic bacteria (or significantly reduce their
levels in) foods without eliminating good bacteria that present on fresh and processed
foods, either via direct spraying on food surfaces or through the packaging materials.
When applied to live animals, phages can be administered via animal feed or spray-
applied to hides or feathers prior to slaughter. It's also used as a disinfectant for
surfaces within the food processing facility. Usage of these lytic bacteriophages makes
the food safer to eat without sacrificing quality, taste and nutritional value of the foods.
While the biological properties of lytic bacteriophages provide advantages for
improving food safety, these properties also lead to some of the limitations and
drawbacks to phage biocontrol. As mentioned previously, bacteriophages are highly
specific and as such, they are only effective against the pathogen of interest. Still, if
foods are contaminated with multiple pathogens, a combination of phage biocontrol
products could be used to target more than one pathogen. Other than that, the bacteria
also can become resistant to the phages at some point during the treatment. To
overcome this problem, one of them is to identify multiple phage strains that can infect
the bacteria so that if it becomes immune to one phage strain, other strains are still
capable of infecting it. Another way is to combine phage therapy with antibiotic
treatment.
Since bacteriophages themselves are also microorganisms, commonly used
disinfectants or chemicals could inactivate them, so their use needs to be carefully
coordinated within the processing line. In addition, the currently marketed phage
preparations require refrigerated storage (typically 28°C). Thus, a good understanding
of the biological properties of bacteriophages and designing optimal application
regimens that consider those properties is essential for the best possible efficacy of
phage biocontrol intervention.
Despite some lingering challenges, phage biocontrol is increasingly being recognized
for its effectiveness in controlling foodborne pathogens in the food processing industry.
The biggest advantage of using phage biocontrol is that wild type lytic phages are
natural antimicrobials that allow targeted elimination of problem foodborne pathogens

3. in foods without deleteriously impacting the natural microflora of foods and other
nutritional or organoleptic qualities of foods.
References:
1. Current Issues in Molecular Biology, MDPI (2021) Vol. 40: 267-302,
https://doi.org/10.21775/cimb.040.267
2. https://www.evergreen.edu/magazine/bacteriophage-good-guys-virus-world
3. https://www.mmgazette.com/using-viruses-to-treat-bacterial-infections-ahmad-
tarmizi-abdul-halim/